Cervical cancer originates from cervical intraepithelial neoplasia (CIN), which continues to develop after the formation of CIN, breaks through the subepithelial basement membrane, and infiltrates the mesenchyme to gradually form, and the process of lesions manifests as normal epithelium, intraepithelial neoplasia, carcinoma in situ, microinfiltrating carcinoma, and infiltrating carcinoma. Cervical carcinoma in situ is between CIN and cervical cancer, which used to be considered as an early stage of cervical cancer and is now classified as CIN grade III (CIN grade III includes severe heterogeneity and carcinoma in situ). When the tissue section of cervical carcinoma in situ was observed under the microscope, cancer cells were seen to occupy the whole layer or nearly the whole layer (≥2/3) within the epithelium and had not yet penetrated the basement membrane of the epithelium to infiltrate the lamina propria below; the nuclei were abnormally enlarged, the nucleoplasmic ratio was significantly increased, the nuclear shape was irregular, the staining was darker, the nuclear schizophrenic images were many, and the cells were crowded, disorganized and non-polar. Carcinoma in situ includes squamous carcinoma in situ and adenocarcinoma in situ, the former is common in clinical practice, while the latter occurs in less than 1%. Carcinoma in situ can spread from the surface along the periphery of the endocervical glands, enveloping the ducts and even replacing part or all of the columnar epithelium, and sometimes the cancer cells can also invade the lumen of the gland and fill it, a phenomenon called carcinoma in situ involving the gland. Clinically, all CIN grade III need treatment, especially for carcinoma in situ, and cervical conization, such as Loop Electric Excision of the Cervix (LEEP) and cold knife conization, is usually used. For those who are old and have no fertility requirements, hysterectomy is feasible. Minimally invasive techniques such as laparoscopic extrafascial total hysterectomy + bilateral salpingo-oophorectomy are commonly used, and pelvic lymph node dissection and abdominal para-aortic lymph node sampling are performed when necessary. Once detected, cervical carcinoma in situ can be cured by active surgical treatment.